This book reviews the results of recent interdisciplinary research studies made on Hydrangea and conducted by INRA and INH teams at Angers (France). Genetic and botanical studies of Hydrangea have revealed the genetic diversity of the genus and enabled a better exploitation of the genetic resources, whereas physiological studies have led to introduce changes in the cultivation technique in order to improve the quality of the plant and its environment. Readership: professionals who create and cultivate Hydrangea cultivars, teachers, students and enthusiasts.